eclipse data supporting Einstein

Measuring the deflection of optical light during eclipses turns out to be very difficult. You can find the results of about a doxen different eclipses from 1919 to about 1973 is most standard text books on relativity. The error bands are fairly large, but generally agree with relativity prediction within about 0.2 arc seconds. By far the better data is in the radio wavelengths, since you don't have to wait for eclipses, and you can use VBLI for incredibly precise measurements of the deflection in all positions in the sky. The current results show a ratio of predicted to observed deflection of about 1.0001 +-.0001. See, for example, Ohanian and Rufinni.

But here's a much more puzzling question. How could someone be unable to find the above information, which is readily avaulable from hundreds of standard references and text books, AND YET he is able to locate an obscure article from 1922 (!) written by an anti-relativityist. This is really a fascinating phenomenon... it's almost as if a certain kind of individial is literally blind and deaf to current up-to-date reliable scientific information, but they absorb sponge-like any anti-scientific material. Truly, someone should make a study of this phenomenon.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by bdw000</i>
<br />The quick question is: do modern eclipse experiments CONVINCINGLY support Einstein and company? For me, plus or minus 50% is NOT convincing.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">The quick answer is yes. Besides the radio source experiments nonneta mentioned, the Cassini spacecraft did a bending experiment in deep space that obsoleted all earlier measures. See physicsweb.org/article/news/7/9/14 or Nature 425:ix & 374-376 (2003). Using signals from Earth to the Cassini spacecraft, the magnitude of the predicted light-bending effect produced by the Sun was shown to agree with GR predictions to within 23 parts per million.

So there is no current credible issue about Einstein's theory being basically correct to first order in the gravitational potential. At best, the controversy is over whether Eddington deserved credit for being the first to show this. IMO, the errors in his experiment have been somewhat exaggerated by a small number of people who were hoping to show that GR was wrong. Now that the point has been reduced to only one of history and credit, there seems insufficient reason to take away Eddington's contribution from the history books. -|Tom|-

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by nonneta</i>
<br />The current results show a ratio of predicted to observed deflection of about 1.0001 +-.0001. See, for example, Ohanian and Rufinni.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Thanks for giving the correspondent a good answer and a partial reference.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">But here's a much more puzzling question. How could someone be unable to find the above information, which is readily avaulable from hundreds of standard references and text books, AND YET he is able to locate an obscure article from 1922 (!) written by an anti-relativityist.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">bdw000 said he was a non-scientist who happened to read a recent book expressing that opinion, and he did the right thing -- he came to a place where objective information is available with no vested interest or axe to grind.

You are new here, so the three Moderators are giving you the benefit of being unfamiliar with the rules. In this case, the important one is that we deal only with science issues, and use no remarks about persons or their motives, competence, or anything else ad hominem.

In particular, do not repeat this kind of remark if you wish to continue posting priveleges here: "it's almost as if a certain kind of individial is literally blind and deaf to current up-to-date reliable scientific information". Keep it about the science, not about any person's views, and all will go well. We are all here to teach and learn, and that process is invariably interrupted by personal remarks of a derogatory nature. -|Tom|-

However, the data confirming Einstein's prediction of light/radio deflection does not necessarily support the "curved spacetime" interpretation, right? Doesn't refraction in a denser elysium atmosphere near a massive body also explain the data?

Thank you very much for your answers.

Re nonneta, Tom is right: I came to the first place I thought might get me the answer.

Sometimes you get tired of millions of hits at google.

Google is definitely wonderful. But sometimes what the nonspecialist needs is the knowledge of people who know what they're talking about.

Science knows much, but ignores practically everything.

I have another question, which I assume has a simple answer:

The sun is not just a theoretical source of gravity. It seems simple enough that there are other physical effects close to the sun, effects that might be powerful, in fact, compared to a few light rays.

The question is: do these eclipse or other EM sorts of experiments take the other effects of the sun into account, or do they know that they are far enough away from the sun that they don't matter?

This is not my idea, of course. I just want to know if it is a valid point to bring up.



Science knows much, but ignores practically everything.